Valved Catheters Including High Flow Rate Catheters

ABSTRACT

A pressure activated two-way slit valve assembly is designed to be used in combination with, but not limited to, a high flow rate catheter to prevent accidental ingestion of air or loss of blood if the closure cap comes off during non-use of the catheter. In addition, the potential for occlusion of the catheter due to blood clots in the catheter and catheter related infection is substantially reduced. The pressure activated two-way slit valve assembly includes a first end, a second end, a wall defining a dumbbell shaped channel, and a flexible, thin disk having a slit and positioned within the pressure activated two-way slit valve assembly to reside within the dumbbell shaped channel. The slit and the dumbbell shaped channel are sized to enable the slit to deform in response to a predetermined pressure differential across the slit to allow fluid to pass therethrough.

PRIORITY CLAIM

The present application is a Continuation application of U.S. patentapplication Ser. No. 10/651,535 filed on Aug. 29, 2003 Entitled “ValvedCatheters Including High Flow Rate Catheters”. The entire disclosure ofthis application is expressly incorporated herein by reference.

TECHNICAL FIELD

This invention relates to valves for catheters. More particularly, thisinvention relates to a valved high flow rate catheter.

BACKGROUND INFORMATION

A high flow rate catheter is a tubular medical device defining one ormore lumens for transporting fluids to and/or from a patient's body at ahigh flow rate, e.g. greater than 200 ml/min. An example of a commonlyused high flow rate catheter is a hemodialysis catheter. Hemodialysiscatheters include at least one lumen for transporting a patient'swaste-filled blood to a dialysis machine for treatment, and anotherlumen for carrying the treated blood back to the patient. Generally,hemodialysis catheters are implanted within a patient's body such that aportion remains within a blood vessel of the patient and a portionextends outside of the patient body to be connected to the dialysismachine.

Conventionally, clamps that compress the lumens of the hemodialysiscatheter have been used to prevent blood loss and to preventingestion ofair through the catheter and into a patient's blood stream (i.e., whenthe catheter is not in use). These clamps tend to degrade thehemodialysis catheter, thereby requiring medical professionals to removeand replace these catheters frequently. In addition, conventional highflow rate catheters are associated with a high occurrence of occlusionformation and infections.

SUMMARY OF THE INVENTION

The present invention generally relates to valves for catheters. Whilethe present invention is described with regard to high flow ratecatheters, it should be noted that the valves described herein may beused in combination with any type of catheter. Devices according to theinvention are typically used to transport fluids to and/or from apatient's body at a high flow rate when the device is in use. It is anobject of this invention to provide a device that protects againstcatastrophic events when the catheter is not in use, such as, forexample, ingestion of air through the device into the patient's bloodstream or blood flowing uncontrollably out from a patient's body. It isanother object of the invention to reduce occlusion formation andinfections associated with conventional high flow rate catheters.

In one aspect, the invention relates to a pressure activated two-wayslit valve assembly for a catheter. The pressure activated two-way slitvalve assembly includes a first end, a second end, a wall defining adumbbell shaped channel that is locatable between the first and secondends, and a flexible, thin disk that includes a slit. The flexible, thindisk is disposed within the pressure activated two-way slit valveassembly such that the slit resides within the dumbbell shaped channeland is substantially perpendicular to a longitudinal axis of thepressure activated two-way slit valve assembly. The slit and thedumbbell shaped channel of the pressure activated two-way slit valveassembly are sized to enable the slit to deform in response to apredetermined pressure differential across the slit to allow fluid topass therethrough.

Embodiments of this aspect of the invention can include the followingfeatures. In one embodiment, the wall of the pressure activated two-wayslit valve assembly further defines connection ports that are located atthe first and second ends. These connection ports are in fluidcommunication with the dumbbell shaped channel. In some embodiments, thefirst end of the pressure activated two-way slit valve assembly has abarbed ending for attaching to a catheter or other similar medicaldevice. In another embodiment, the second end of the pressure activatedtwo-way slit valve assembly has a luer ending for attaching to one of adialysis machine or an end cap. In some embodiments, the flexible, thindisk has a straight slit. In other embodiments, the flexible, thin diskhas an H-shaped slit. In another embodiment, the slit of the flexible,thin disk has a saw-tooth wave shape. In still yet another embodiment,the pressure activated two-way slit valve assembly includes a safetyrotatable valve key that overrides the functionality of the pressureactivated two-way slit valve assembly and maintains the pressureactivated two-way slit valve assembly in an open position. In a furtherembodiment, the safety rotatable valve key is attached to the second endof the pressure activated two-way slit valve assembly.

In another aspect, the invention relates to a medical device. Themedical device includes a catheter including a distal end, a proximalend, and a housing that defines one or more lumens that extend betweenthe distal end and the proximal end. The distal end of the catheter isopen whereas the proximal end is attached to a pressure activatedtwo-way slit valve assembly comprising a first end, a second end, a walldefining a dumbbell shaped channel that is locatable between the firstand second ends, and a flexible, thin disk including a slit. Theflexible, thin disk is disposed within the pressure activated two-wayslit valve assembly such that the slit resides within the dumbbellshaped channel and is substantially perpendicular to a longitudinal axisof the pressure activated two-way slit valve assembly. The slit and thedumbbell shaped channel are sized to enable the slit to deform inresponse to a predetermined pressure differential across the slit toallow fluid to pass therethrough.

Embodiments of this aspect of the invention can include the followingfeatures. In one embodiment, the wall of the pressure activated two-wayslit valve assembly further defines connection ports that are located atthe first and second ends of the pressure activated two-way slit valveassembly and are in fluid communication with the dumbbell shapedchannel. In another embodiment, the flexible, thin disk has an H-shapedslit. Alternatively, in another embodiment, the slit of the flexible,thin disk has a saw-tooth wave shape. In some embodiments, the pressureactivated two-way slit valve assembly further includes a safetyrotatable valve key that overrides the functionality of the pressureactivated two-way slit valve assembly and maintains the pressureactivated two-way slit valve assembly in an open position. In a furtherembodiment, the safety rotatable valve key is attached to the second endof the pressure activated two-way slit valve assembly. In still yetanother embodiment, the housing of the catheter is coated with ananti-infective coating to inhibit cell and bacteria growth.

In general, in another aspect, the invention relates to a valveddialysis catheter. The valved dialysis catheter, according to thisaspect of the invention, includes an open-ended single or multi-lumencatheter including at least one lumen for withdrawing blood from apatient for dialysis and at least one lumen for returning blood from adialysis machine to the patient. Each lumen of the open-endedmulti-lumen catheter includes a pressure activated two-way slit valveassembly. Each pressure activated two-way slit valve assembly includes afirst end that is connected to the open-ended single or multi-lumencatheter, a second end that is connectable to a dialysis machine, a wallextending between a first end and a second end and defining a dumbbellshaped channel that is locatable between the first and second ends, anda flexible, thin disk. The flexible thin disk includes a slit and isdisposed within the pressure activated two-way slit valve assembly suchthat the slit resides within the dumbbell shaped channel and issubstantially perpendicular to a longitudinal axis of the pressureactivated two-way slit valve assembly. Both of the slit and the dumbbellshaped channel are sized to enable the slit to deform in response to apredetermined pressure differential across the slit to allow fluid topass therethrough.

Embodiments of this aspect of the invention can include the followingfeatures. In one embodiment, the wall of the pressure activated two-wayslit valve assembly further defines connection ports that are located atthe first and second ends of the pressure activated two-way slit valveassembly. These connection ports are in fluid communication with thedumbbell shaped channel. In some embodiments, the first end of thepressure activated two-way slit valve assembly has a barbed endingconnecting the pressure activated two-way slit valve assembly with themulti-lumen catheter. In other embodiments, the second end of thepressure activated two-way slit valve assembly has a luer ending forattaching to one of a dialysis machine or an end cap. In anotherembodiment, the flexible, thin disk has an H-shaped slit. Alternatively,in a further embodiment, the slit of the flexible, thin disk has asaw-tooth wave shape. In some embodiments, the pressure activatedtwo-way slit valve assembly includes a safety rotatable valve key thatoverrides the functionality of the pressure activated two-way slit valveassembly and maintains the pressure activated two-way slit valveassembly in an open position. Other embodiments feature a single ormulti-lumen catheter with an anti-infective external surface and furtherembodiments feature a single or multi-lumen catheter with ananti-infective internal surface.

In general, in another aspect, the invention relates to a method forpreventing air ingestion in a valved catheter and preventing blood lossfrom the valved catheter. The method, according to this aspect of theinvention, includes providing the medical device including the catheterdescribed above, and using the pressure activated two-way slit valveassembly to prevent air ingestion through the catheter and into apatient's blood stream and to prevent blood loss while the valvedcatheter is not in use.

Embodiments of this aspect of the invention can include the followingfeatures. In one embodiment, the predetermined pressure differentialacross the slit of the disk within the pressure activated two-way slitvalve is between about 50 cm of water and about 120 cm of water. In analternative embodiment, the predetermined pressure differential isbetween about 80 cm of water and 120 cm of water. In other embodiments,the valve is designed to open at any predetermined pressure selected bya manufacturer.

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent from the following descriptionand the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention.

FIG. 1 is schematic view of one embodiment of a pressure activatedtwo-way slit valve assembly according to the invention.

FIG. 2 is an exploded view of the pressure activated two-way slit valveassembly of FIG. 1.

FIG. 3 is a cross-sectional view of a first end portion of the pressureactivated two-way slit valve assembly, taken along line AA of FIG. 1.

FIG. 4 is a cross-sectional view of a second end portion of the pressureactivated two-way slit valve assembly, taken along line BB of FIG. 1.

FIG. 5 is a plan-view of an alternative embodiment of a lumen extendingthrough the first and second end portions.

FIG. 6 is another plan-view of another alternative embodiment of a lumenextending through the first and second end portions.

FIG. 7 is a plan-view of a flexible, thin disk that is disposed withinthe pressure activated two-way slit valve assembly of FIG. 1.

FIG. 8 is a plan-view of another embodiment of a flexible, thin disk.

FIG. 9 is a schematic view of one embodiment of a medical device thatincludes a catheter and two pressure activated two-way slit valveassemblies.

FIG. 10 is a cross-sectional view of a portion of the catheter, takenalong line CC of FIG. 9.

FIG. 11 is a cross-sectional view of a portion of a tubular elementextending off from the catheter, taken along DD of FIG. 9.

FIG. 12 is a schematic view of an embodiment of a safety, rotatablevalve key.

FIG. 13 is a schematic view of the safety, rotatable valve key of FIG.12 attached to a second end of the pressure activated two-way slit valveassembly of FIG. 1.

FIG. 14 is a schematic view of a valved dialysis catheter including twopressure activated two-way slit valve assemblies as used duringhemodialysis.

DESCRIPTION

The kidneys are a pair of organs located near the backbone that filterand remove waste products from a human being's blood. Patients whosuffer from kidney failure must undergo hemodialysis, a process in whichwaste products from the patient's blood are removed through passingtheir blood through a dialysis machine. Generally, these patientsrequire dialysis treatments once every three days.

Hemodialysis catheters, which are a type of high flow rate catheter, areused to transport such a patient's blood to and from the dialysismachine for treatment. Typically, a portion of the hemodialysis catheteris implanted within a patient's body while a reminder of thehemodialysis catheter extends out from the body and is easily attachedto the dialysis machine.

Other uses for high flow rate catheters can include rapid infusion ofblood and blood products to a patient and infusion of saline to adehydrated patient.

Some of the biggest complaints with conventional high flow ratecatheters are occlusions, thrombus, and catheter-related infections.Generally, these complications arise due to, at least in part, poorfluid flow dynamics of the catheter and/or catheter parts, including,but not limited to, valve assemblies.

The present invention concerns valve assemblies for high flow ratecatheters having a single lumen or multiple lumens. A valve assembly,according to the present invention, in combination with a catheterallows for efficient fluid transport to and/or from a patient's body.This invention also concerns a valve assembly for a high flow ratecatheter that prevents ingestion of air from entering the high flow ratecatheter and prevents blood loss when the catheter is not in use.

Referring to FIG. 1, a pressure activated two-way slit valve assembly 10according to the invention includes a first end 12, a second end 14, anda wall 15 extending from the first end 12 to the second end 14. The wall15 can be made from any relatively rigid, biocompatible, polymer suchas, for example, polycarbonate, polyethylene, or ultem® and includes afemale housing portion 16 and a male housing portion 18. The malehousing portion 18 friction fits within the female housing portion 16,thereby holding the two portions 16, 18 together. In addition tofrictional forces, an adhesive can be used to secure a bond between thefemale and male housing portions 16, 18. Alternatively, the femalehousing portion 16 can be thermally, chemically, or ionically bonded tothe male housing portion 18.

Located at the first and second ends 12, 14 are connection ports 17 and19 used to interconnect the pressure activated two-way slit valveassembly 10 to other medical devices, such as, for example, catheters,dialysis machines, and end caps. The connection ports 17, 19 can havebarbed or luer endings as shown in FIGS. 1 and 2 to aid in attachmentbetween a medical device and the pressure activated two-way slit valveassembly 10. For example, the connection port 17 has barbed endings 47and the connection port 19 has luer endings 48.

Disposed within the pressure activated two-way slit valve assembly 10 isa flexible, thin disk 24, shown in FIG. 2, that is “sandwiched” betweenthe female housing portion 16 and the male housing portion 18. Theflexible, thin disk 24 is preferably made from silicone or other similarflexible polymer and includes a slit 26. The flexible, thin disk 24 ispositioned within the pressure activated two-way slit valve assembly 10such that the slit 26 is perpendicular to line LL, a longitudinal axis25 of the pressure activated two-way slit valve assembly 10. The slit 26remains in a closed position as shown in FIG. 2 until a pressuredifferential having a predetermined force exists within the pressureactivated two-way slit valve assembly 10. Once the pressure differentialcrosses over this predetermined force threshold, the slit 26 separates,thereby allowing blood or fluid to flow therethrough.

The pressure activated two-way slit valve assembly 10 also includes adumbbell shaped channel 20 that is defined by wall 15 and surrounds theflexible, thin disk 24. As shown in FIGS. 3 and 4, the dumbbell shapedchannel 20 is disposed within both of the female housing portion 16 andthe male housing portion 18. The dumbbell shaped channel 20 has a middlechannel portion 27 disposed between and in fluid communication with twolarge cross-sectional area channel portions 28. The middle portion 27has a smaller cross-sectional area than the two large cross-sectionalarea channel portions 28 and thus, restricts the slit 26 from openingprematurely (i.e., under conditions where the pressure differential isbelow threshold) by decreasing the amount of channel cross-sectionalarea in a pressure sensitive region. In some embodiments, each largecross-sectional area channel portion 28 has 3 times the cross-sectionalarea as the middle portion 27. This extra cross-sectional area of thelarge cross-sectional area channel portions 28 provides the pressureactivated two-way slit valve assembly 10 with a large amount of fluidtransport area, to maximize fluid flow rates through the pressureactivated two-way slit valve assembly 10 once the slit 26 has crackedopen. These large cross-sectional area channel portions 28 allow theflow rate through the pressure activated two-way slit valve assembly 10to maintain a flow rate of upto 500 ml/min. In some embodiments, thelarge cross-sectional area channel portions 28 allow the flow rate toapproach a flow range of about 400 ml/min to 500 ml/min, which is agreater flow rate range than typically achieved in conventional valvedhigh flow rate catheters. An advantage of this greater flow rate rangeis a decrease in actual catheter use or treatment time. For example, ahemodialysis catheter having a greater flow rate range means that therewill be a decrease in dialysis treatment time, which is a greaterconvenience for both a dialysis patient and for an attending medicalprofessional.

The shape of the dumbbell shaped channel 20 can be slightly modified toproduce alternative embodiments of the pressure activated two-way slitvalve assembly 10. As depicted in FIGS. 5 and 6, the perimeter of thelarge cross-sectional area channel portion 28 can be extended to form anelongated dumbbell shaped channel 20 b, shown in FIG. 5, or an octagonaldumbbell shaped channel 20 c, as shown in FIG. 6. In some embodiments,the size of the middle channel portion 27 is minimized such that the twolarge cross-sectional area channel portions 28 are separated by amillimeter or less. Other similar embodiments are also possible as longas each large cross-sectional area channel portion 28 has a largercross-sectional area than the middle portion 27.

Each of the female and male housing portions 16, 18 can taper, asdepicted in FIG. 1, from an area of greatest diameter locatedsubstantially at connection area 23 to an area of lesser diameter 21.The dumbbell shaped channel 20 disposed within the female and malehousing portions 16, 18 tapers along with these portions 16, 18. As thedumbbell shaped channel 20 tapers the shape of the dumbbell shapedchannel 20 gradually transforms from a dumbbell structure to an oval orcircular structure.

Located within the dumbbell shaped channel 20, between the femalehousing portion 16 and the male housing portion 18, is the flexible,thin disk 24 with slit 26. The slit 26 can be a straight slit or, insome embodiments, be H-shaped as shown in FIG. 7. Alternatively, theslit 26 can have a saw-tooth wave shape as shown in FIG. 8. In any case,the size and shape of the slit 26 and the size of the dumbbell shapedchannel 20 are designed to enable the slit to deform or crack open whena predetermined pressure differential exists across the pressureactivated two-way slit valve assembly 10. Generally, the size of theslit 26 and the dumbbell shaped channel 20 are designed to preventdeformation of the slit 26 until a pressure differential of at leastabout 50 cm of water exists, thereby minimizing accidental openings ofslit 26, which could lead to bleed out or air ingestion. In a preferredembodiment, the dumbbell shaped channel 20 is designed to preventdeformation of the slit 26 until a pressure differential within a rangeof about 50 cm of water to about 120 cm of water exists. In a morepreferred embodiment, the dumbbell shaped channel is designed to preventdeformation of the slit until a pressure differential within a range ofabout 80 cm of water to about 120 cm of water exists. It is alsoimportant to note that the valve may be designed to have the slit crackopen at any pressure differential preferred for a particular medicalapplication.

The two-way slit valve assembly 10 allows fluid to flow therethrough ineither a proximal direction (i.e., from the first end 12 towards thesecond end 14) or a distal direction (i.e., from the second end 14towards the first end 12). As long as the pressure differential acrossthe flexible, thin disk 24 is greater than the threshold, the slit 26will open automatically and will allow fluids to pass therethrough ineither direction.

The particular threshold pressure differential is determined by one ormore of the following factors: (1) the thickness of the flexible, thindisk 24, (2) the size of the slit 26, (3) the hardness of the materialused to form the flexible, thin disk 24, and (4) the cross-sectionalarea of the dumbbell shaped channel 20 within each of the female housingportion 16 and the male housing portion 18. For example, the thresholdpressure differential value of the two-way slit valve assembly 10 can becustomized to a particular value by varying the factors listed above.Thus, if a particular application of the two-way slit valve assembly 10required a valve, which could open a very low threshold pressuredifferential value, the material and thickness of the flexible, thindisk 24 and the length of the slit 26 can be selected to accomplish thisusage.

In some applications of the two-way slit valve assembly 10, it isimportant to provide the valve with two different threshold pressuredifferential values. That is one particular threshold pressuredifferential value for fluids flowing in the proximal direction andanother different threshold pressure differential value for fluidsflowing in the distal direction. Embodiments of two-way slit valveassemblies 10 used in these applications can include a dumbbell shapedchannel 20 that has a different cross-sectional area dimension in thefemale housing portion 16 than in the male housing portion 18, so ascreate two direction sensitive threshold pressure differential values.

The two-way slit valve assembly 10 can be attached to a catheter havinga single lumen or alternatively multiple lumens. By way of illustrationthe following example describes usage of the two-way slit valve assemblyin connection with a hemodialysis catheter (a high flow rate catheter)that has two or more lumens.

Referring to FIG. 9, shown is a portion of a hemodialysis catheter 40attached to two pressure activated two-way slit valve assemblies 10 a,10 b according to the invention. The hemodialysis catheter 40 has twodistinct lumens 42 a, 42 b disposed within, as shown in FIG. 10. One ofthe lumens 42 a provides a path for waste-filled blood to exit thepatient's body, while the opposing lumen 42 b provides a path for bloodafter dialysis treatment to return to the body. An adapter 34, shown inFIG. 9 and affixed to an end of the hemodialysis catheter 40 furtherseparates these two distinct lumens 42 a, 42 b into individual tubularelements generally called extension legs 30.

Each extension leg 30 has a single lumen 32 disposed within as shown inFIG. 11. The pair of extension legs 30 a, 30 b work in combination. Oneof the extension legs 30 a is in fluid connection with the lumen 42 athat transports waste-filled blood to a dialysis machine, while theother extension leg 30 b is connected to the lumen 42 b that carriestreated, clean blood back to the patient. Each extension leg 30 a, 30 bis connected to a pressure activated two-way slit valve assembly 10 thatprevents blood from flowing therethrough when dialysis is not inprocess. The hemodialysis catheter 40 in combination with the extensionlegs 30 a, 30 b and pressure-activated slit valve assemblies 10 a, 10 bcan be secured to a patient's body using a wing clip 36 as shown in FIG.9.

The embodiments shown in FIGS. 9 and 10 depict a hemodialysis catheter40 having two lumens 42 a, 42 b. In alternative embodiments, not shown,the hemodialysis catheter 40 or other high flow rate catheter can havemore than two lumens. In these embodiments, the additional lumens (i.e.,the third, fourth, and so on) can provide access ports for delivery ofliquid medicines or other fluids to the patient or for collecting bloodspecimens from the patient's body. Additional extension legs 30 toconnect to the additional lumens 42 would be needed. Each additionalextension leg 30 can be outfitted with one pressure activated two-wayslit valve assembly 10 if desired.

In some embodiments of this invention, an outer surface 45 of thehemodialysis catheter 40 is coated with an anti-infective coating, suchas an antibiotic (for example, tetracycline or doxycycline) or anantimicrobial. These anti-infective coating help prevent the build up ofbacteria on the surface of the hemodialysis catheter 40, thereby helpingto minimize the possibility of complications caused by infection. Thehemodialysis catheter can also have a similar anti-infective coatingalong a surface 47 of the lumen 42 a, 42 b. Likewise, the anti-infectivecoating present along the surface 47 helps to prevent infection withinthe hemodialysis catheter 40.

An additional feature that can be incorporated into the invention is asafety rotatable valve key 50, an embodiment of which is shown in FIGS.12 and 13. The safety rotatable valve key 50 can be used force andmaintain the slit 26 open to allow for immediate and constant access tothe lumens 42 of the hemodialysis catheter 40. The safety rotatablevalve key 50 includes an inner tube 52 that can be positioned to extendthrough the slit 26 when the safety rotatable valve key 50 is rotatedfrom a first position to a second position. The safety rotatable valvekey 50 can include a luer ending 54 for attachment to a dialysis machineor an end cap. In addition, the safety rotatable valve key 50 can alsoinclude a pair of finger knobs 56 a, 56 b to aid a medical professionalin rotating the safety rotatable valve key 50.

In operation, a portion of the hemodialysis catheter 40 is implantedwithin the patient's body and an open end of the hemodialysis catheter40 is located within the patient's blood stream. To begin hemodialysis,endcaps are removed from the second end 14 of each pressure activatedtwo-way slit valve assembly 10 a, 10 b attached to the hemodialysiscatheter 40. The second end 14 is then secured to a dialysis machine 60,shown in FIG. 14, that supplies sufficient vacuum force to create therequired pressure differential across one the slit 26 of one of thepressure activated two-way slit valve assemblies 10 a. Once the slit 26has cracked open, blood will flow from the patient's body through thehemodialysis catheter 40 to the dialysis machine 60 for treatment (i.e.,removal of waste products from the blood). Simultaneously, the dialysismachine 60 forces treated blood through another pressure activatedtwo-way slit valve assembly 10 b and into the hemodialysis catheter tobe returned to the patient's body.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill in the artwithout departing from the spirit and scope of the invention. Theinvention is not to be limited only to the preceding illustrativedescription.

1-26. (canceled)
 27. A pressure activated two-way slit valve assemblyfor a catheter, the pressure activated two-way slit valve assemblycomprising: a first end; a second end; a wall extending between thefirst end and the second end, the wall defining a channel having across-section located between the first end and the second end, whereinthe cross-section includes at least three portions, at least two of theportions being substantially larger than a third portion, thecross-section being perpendicular to a longitudinal axis of the of thepressure activated two-way slit valve assembly; and a two-way slit valvedisposed within the channel between the first end and the second end,wherein a slit of the slit valve and the channel are sized to enable theslit to deform in response to a predetermined pressure differentialacross the slit to allow fluid to pass therethrough.
 28. The pressureactivated two-way slit valve assembly of claim 27, wherein the wallfurther defines connection ports located at the first end and the secondend, the connection ports being in fluid communication with the channel.29. The pressure activated two-way slit valve assembly of claim 28,wherein the first end comprises a barbed ending for attaching to acatheter.
 30. The pressure activated two-way slit valve assembly ofclaim 28, wherein the second end comprises a luer ending for attachingto one of a dialysis machine and an end cap.
 31. The pressure activatedtwo-way slit valve assembly of claim 27, wherein the slit comprises anH-shape.
 32. The pressure activated two-way slit valve assembly of claim27, wherein the slit comprises a saw-tooth wave shape.
 33. The pressureactivated two-way slit valve assembly of claim 27, further comprising asafety rotatable valve key.
 34. The pressure activated two-way slitvalve assembly of claim 33, wherein the safety rotatable valve key isattached to the second end.
 35. A medical device comprising: a cathetercomprising a distal end, a proximal end, and a housing defining at leastone or more lumens extending between the distal end and the proximalend, the distal end being open, and the proximal end including apressure activated two-way slit valve assembly, the two-way slit valveassembly comprising: a first end, a second end, a wall extending betweenthe first end and the second end, the wall defining a channel having across-section located between the first end and the second end, whereinthe cross-section includes at least three portions, at least two of theportions being substantially larger than a third portion, thecross-section being perpendicular to a longitudinal axis of the of thepressure activated two-way slit valve assembly; and a two-way slit valvedisposed within the channel between the first end and the second end,wherein a slit of the slit valve and the channel are sized to enable theslit to deform in response to a predetermined pressure differentialacross the slit to allow fluid to pass therethrough.
 36. The medicaldevice of claim 35, wherein the wall of the pressure activated two-wayslit valve assembly further defines connection ports located at thefirst end and the second end, the connection ports being in fluidcommunication with the dumbbell shaped channel.
 37. The medical deviceof claim 35, wherein the slit of the pressure activated two-way slitvalve assembly comprises an H-shape.
 38. The medical device of claim 35,wherein the slit of the pressure activated two-way slit valve assemblycomprises a saw-tooth wave shape.
 39. The medical device of claim 35,wherein the pressure activated two-way slit valve assembly furthercomprises a safety rotatable valve key.
 40. The medical device of claim39, wherein the safety rotatable valve key is attached to the second endof the pressure activated two-way slit valve assembly.
 41. The medicaldevice of claim 27, wherein the housing of the catheter is coated withan anti-infective coating to inhibit bacteria growth.
 42. A valveddialysis catheter comprising: an open-ended multi-lumen catheterincluding at least one lumen for withdrawing blood form a patient fordialysis and at least one lumen for retuning blood from a dialysismachine to the patient, each lumen of the open-ended multi-lumencatheter including a pressure activated two-way slit valve assembly,each two-way slit valve assembly comprising: a first end, a second end,a wall extending between the first end and the second end, the walldefining a channel having a cross-section located between the first endand the second end, wherein the cross-section includes at least threeportions, at least two of the portions being substantially larger than athird portion, the cross-section being perpendicular to a longitudinalaxis of the of the pressure activated two-way slit valve assembly; and atwo-way slit valve disposed within the channel between the first end andthe second end, wherein a slit of the slit valve and the channel aresized to enable the slit to deform in response to a predeterminedpressure differential across the slit to allow fluid to passtherethrough.
 43. The valved dialysis catheter of claim 42, wherein thewall of the pressure activated two-way slit valve assembly furtherdefines connection ports located at the first end and the second end,the connection ports being in fluid communication with the dumbbellshaped channel.
 44. The valved dialysis catheter of claim 43, whereinthe first end of the pressure activated two-way slit valve assemblycomprises a barbed ending.
 45. The valved dialysis catheter of claim 43,wherein the second end of the pressure activated two-way slit valveassembly comprises a luer ending.
 46. The valved dialysis catheter ofclaim 42, wherein the slit of the pressure activated two-way slit valveassembly comprises an H-shape.
 47. The valved dialysis catheter of claim42, wherein the slit of the pressure activated two-way slit valveassembly comprises a saw-tooth wave shape.
 48. The valved dialysiscatheter of claim 42, wherein the pressure activated two-way slit valveassembly further comprises a safety rotatable valve key.
 49. The valveddialysis catheter of claim 42, wherein the open-ended multi-lumencatheter further comprises an anti-infective external surface.
 50. Amethod for preventing air ingestion in a valved catheter, the methodcomprising the steps of: providing a catheter comprising a distal end, aproximal end, and a housing defining at least one or more lumensextending between the distal end and the proximal end, the distal endbeing open, the proximal end including a pressure activated two-way slitvalve assembly comprising: a first end, a second end, a wall extendingbetween the first end and the second end, the wall defining a channelhaving a cross-section located between the first end and the second end,wherein the cross-section includes at least three portions, at least twoof the portions being substantially larger than a third portion, thecross-section being perpendicular to a longitudinal axis of the of thepressure activated two-way slit valve assembly, and a two-way slit valvedisposed within the channel between the first end and the second end,wherein a slit of the slit valve and the channel are sized to enable theslit to deform in response to a predetermined pressure differentialacross the slit to allow fluid to pass therethrough; and inserting thedistal end of the catheter within a blood vessel.
 51. The method ofclaim 50, wherein the predetermined pressure differential is betweenabout 50 cm of water to about 120 cm of water.
 52. The method of claim50, wherein the predetermined pressure differential is between about 80cm of water to about 120 cm of water.
 53. A pressure activated two-wayslit valve assembly for a catheter, the pressure activated two-way slitvalve assembly comprising: a housing including a channel, wherein: across-section of the channel is perpendicular to a longitudinal axis ofthe housing, and at least two portions of the cross-section aresubstantially larger than a third portion of the cross-section; and atwo-way slit valve disposed within the channel, wherein a slit of theslit valve is longitudinally aligned with the third portion.